1. Field of the Invention
The present invention relates to a plasma processing apparatus for performing a predetermined process using a plasma.
2. Description of the Related Art
In the manufacture of, for example, a semiconductor integrated circuit, plasma is utilized in the steps of ashing, etching, CVD and sputtering treatments in order to promote the ionization of a processing gas, the chemical reaction, etc. It was customary in the past to use in many cases a parallel plate type plasma apparatus using a high frequency (RF) energy as a means for generating a plasma. Recently, proposed is a high frequency induction type plasma processing apparatus using a spiral antenna because the plasma processing apparatus of this type permits a desirable energy density distribution of the plasma, makes it possible to control highly accurately the bias potential between the plasma and the susceptor, and is effective for diminishing the contamination with the heavy metal coming from the electrode. As described in, for example, European Patent Laid-Open Specification No. 379828, the high frequency induction type plasma processing apparatus comprises a processing chamber and a wafer-supporting plate positioned within the processing chamber. In general, the upper wall portion, which is positioned to face the wafer-supporting plate, of the processing chamber is formed of an insulating material such as a silica glass. Also, a spiral antenna is fixed to the outer wall surface of the insulating region of the processing chamber. A high frequency current is allowed to flow through the antenna so as to generate a high frequency electromagnetic field. The electrons flowing within the region of the electromagnetic field are allowed to collide against neutral particles within the processing gas so as to ionize the gas and, thus, to generate a plasma.
In the high frequency induction type plasma processing apparatus, a plasma is formed within the inner space of the processing chamber right under the spiral antenna. Concerning the density distribution of the plasma thus formed relative to the intensity of the electric field, the highest plasma density is formed about midway between the center and the outermost region in the radial direction of the spiral antenna, and the plasma density is gradually lowered toward the center and toward the outermost region of the spiral antenna.
In other words, the plasma density is uneven in the radial direction of the spiral antenna. The plasma of the uneven distribution in the radial direction is diffused from the higher density region toward the lower density region, with the result that the plasma density is made considerably uniform near a semiconductor region positioned below the plasma-forming region.
In the conventional plasma processing apparatus of this type, however, the plasma diffusion in the radial direction tends to cause the plasma density in the central region of the semiconductor wafer to be higher than in the outer peripheral region of the wafer, leaving room for further improvement in the uniformity and reproducibility of the plasma processing.
The present invention, which has been achieved in view of the situation described above, is intended to provide a high frequency induction type plasma processing apparatus which permits a highly uniform plasma density in the region around an object to be processed and is excellent in its uniformity and reproducibility of the plasma processing.
According to a first aspect of the present invention, there is provided a plasma processing apparatus, comprising:
a processing chamber in which an object to be processed is arranged;
a processing gas introducing means for introducing a processing gas into the processing chamber;
an induction member arranged in that region on the outer surface of the processing chamber which is positioned to correspond to the object to be processed, an insulator being interposed between the induction member and the processing chamber, and a high frequency power being supplied to the induction member so as to form an induction electric field near the object to be processed; and
a paramagnetic member arranged to overlap at least partially with the induction member.
According to a second aspect of the present invention, there is provided a plasma processing apparatus, comprising:
a processing chamber in which an object to be processed is arranged;
a processing gas introducing means for introducing a processing gas into the processing chamber; and
an induction member arranged in that region on the outer surface of the processing chamber which is positioned to correspond to the object to be processed, an insulator being interposed between the induction member and the processing chamber, a high frequency power being supplied to the induction member so as to form an induction electric field near the object to be processed, and the induction member being spiral such that a space is provided in its central region.
According to a third aspect of the present invention, there is provided a plasma processing apparatus, comprising:
a processing chamber in which an object to be processed is arranged;
a processing gas introducing means for introducing a processing gas into the processing chamber; and
an induction member arranged in that region on the outer surface of the processing chamber which is positioned to correspond to the object to be processed, an insulator being interposed between the induction member and the processing chamber, a high frequency power being supplied to the induction member so as to form an induction electric field near the object to be processed, and the induction member being spiral and having an outer region and a central region differing from each other in its pitch.
According to a fourth aspect of the present invention, there is provided a plasma processing apparatus, comprising:
a processing chamber in which an object to be processed is arranged;
a processing gas introducing means for introducing a processing gas into the processing chamber; and
at least two induction members each arranged in that region on the outer surface of the processing chamber which is positioned to correspond to the object to be processed, an insulator being interposed between the induction members and the processing chamber, a high frequency power being supplied to the induction member so as to form an induction electric field near the object to be processed, each of the two induction members forming a single loop, and the two induction members being arranged in a concentric configuration.
According to a fifth aspect of the present invention, there is provided a plasma processing apparatus, comprising:
a processing chamber in which an object to be processed is arranged;
a processing gas introducing means for introducing a processing gas into the processing chamber; and
two induction members each arranged in that region on the outer surface of the processing chamber which is positioned to correspond to the object to be processed, an insulator being interposed between the induction members and the processing chamber, a high frequency power being supplied to the induction member so as to form an induction electric field near the object to be processed, and one of the two induction members forming a single loop with the other being spiral, these two induction members being arranged in a concentric configuration.
According to a sixth aspect of the present invention, there is provided a plasma processing apparatus, comprising:
a processing chamber in which an object to be processed is arranged;
a processing gas introducing means for introducing a processing gas into the processing chamber; and
two induction members each arranged in that region on the outer surface of the processing chamber which is positioned to correspond to the object to be processed, an insulator being interposed between the induction members and the processing chamber, a high frequency power being supplied to the induction member so as to form an induction electric field near the object to be processed, and each of the two induction members being spiral, these two induction members being arranged in a concentric configuration.
Further, according to a seventh aspect of the present invention, there is provided a plasma processing apparatus, comprising:
a processing chamber in which an object to be processed is arranged;
a processing gas introducing means for introducing a processing gas into the processing chamber;
an induction member arranged in that region on the outer surface of the processing chamber which is positioned to correspond to the object to be processed, an insulator being interposed between the induction member and the processing chamber, and a high frequency power being supplied to the induction member so as to form an induction electric field near the object to be processed; and
a magnetic member arranged in the vicinity of the induction member outside the processing chamber.